1. Field of the Invention
The invention relates to the field of cross-country skiing.
2. Description of Background and Relevant Information
For a long time, cross-country skis had been used with rudimentary devices for binding the boot to the ski. The boot sole had, for example, a tongue or a binding strap extending beyond the front end of the boot and which was held in a lock arranged forward from the position of the boot in relation to the ski.
It has been realized that this type of binding has two major drawbacks. During the practice of the conventional alternate step technique, it has been noticed that these systems necessitated a forward rotational movement of the boot in relation to the ski about an axis which is located far ahead of the foot. The result is a movement of the foot that is not natural, far from the foot rolling movement that can be observed when walking. During the practice of the skating step, these systems also have the drawback of providing only a very poor lateral guidance of the boot in relation to the ski.
In order to remedy these problems, systems for binding the boot to the ski, whereby the boot waG is articulated on the ski about an axis arranged immediately behind the front end of the sole, were introduced in the 1980s. These systems have at least part of the binding device arranged under the boot sole. This enables the boot pivot point to be moved back in relation to the ski and to rigidify the torsional strength of the boot/binding assembly during the practice of the skating step.
The device described in the document FR-2.739.788 shows that the articulation axis of the boot as well as the elastic return means, which tend to apply the boot flat against the ski, are located under the sole.
Other devices, which are described, for example, in the documents FR-2.742.060, FR-2.782.652, WO-01/93963, WO-02/05907, or WO-02/087710, confirm that the trend is to seek a positioning of the binding device that is as much under the boot sole as possible, and no longer mainly at the front of the boot.
However, many of these systems have the drawback of being positioned between the boot and the ski, and of particularly raising the boot in relation to the ski. The primary consequence of this is not allowing for a direct support of the boot on the ski, which can negatively affect a proper support on the ski edges, especially for the practice of the skating step. In addition, in the known systems, the support of the boot on the ski does not occur directly on the ski, but rather generally by means of a baseplate which covers more or less the entire width of the ski upper surface, such as shown, for example, in the document EP-878.218. The presence of such a baseplate increases the height of the boot position and has a tendency to also distribute the pressure over the width of the ski whereas, during edge setting, one wishes instead to concentrate a maximum of the ski pressure on one of the edges, typically the inner edge.